HDU-1247 Hat's Words (字典树）

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经典的字典树，debug爽歪歪。

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Code:

#include<bits/stdc++.h>
using namespace std;
const int MAXN = 500000;
int ch[MAXN][26], tag[MAXN], tot = 1;
char word[50010][80];

void Insert(char *s) {
    int now = 1, id;
    while(*s) {
        id = *s - 'a';
        if (ch[now][id]) now = ch[now][id];
        else now = ch[now][id] = ++tot;
        ++s;
    }
    ++tag[now];
}

bool find(char *s) {
    int now = 1, id;
    while(*s) {
        id = *s - 'a';
        if (ch[now][id]) now = ch[now][id];
        else return false;
        ++s;
    }
    if (tag[now]) return true;
    else return false;
}

bool find_hat(char *s) {
    char ss[80];
    int now = 1, id, len = strlen(s);
    for (int i = 1; i <= len; ++i) {
        id = s[i-1] - 'a';
        if (ch[now][id]) now = ch[now][id];
        if (tag[now] && i < len) {
            strcpy(ss, s+i);
            if (find(ss)) return true;
        }
    }
    return false;
}

int main() {
    int num = 0;
    memset(tag, 0, sizeof(tag));
    while(~scanf("%s", word[num]))
        Insert(word[num++]);
    for (int i = 0; i < num; ++i)
        if(find_hat(word[i]))
            printf("%s
", word[i]);

    return 0;
}